Resuscitator



March 29, 1960 P. F. EARLY 2,930,375

REsUscITAToR Filed Sept. 25, 1957 2 Sheets-Sheet l PAUL E EARLY INVENTOR.

ze :soV 27o 28o s March 29, 1960 P, F, EARLY 5 2,930,375

RESUSCITATOR Filed Sept. 25, 1957 2 Sheets-Sheet 2 se se 4 76 PAUL F. EARLY INVENTOR.

BY M. w

United States Patent RESUSCITATOR Paul F. Early, Dayton, Ohio, assignor to Globe I ndustries, Inc., Dayton, Ohio, a corporation of Ohio Application September 25, 1957, Serial No. 686,131

18 Claims. (Cl. 12S-29) This invention relates to a resuscitator for supplying a breathing gas to a patient, and more particularly to a resuscitator control' assembly of novel design permitting independent regulation of the patients inhalation and exhalation, although not necessarily so limited.

The present resuscitator is of the type that operates from a source of gas under pressure wherein the gas is conveyed to the patients lungs to force inhalation by the patient, and the flow of gas is diverted to an aspirator assembly for evacuating gas from the patients lungs to force exhalation. In prior devices of this type, the breathing cycle is regulated by adjusting the ow of gas from the source of gas under pressure, such that the breathing frequency is variable. However, in these types, the ratio of the inhalation time to the exhalation time remains substantially constant, such that it is not possible to effect a decrease in the time required for exhale tion without effecting a corresponding decrease in the time required for inhalation. Similarly, it is generally the case in earlier resuscitators of this type that the maximum and minimum lung pressures created by the resuscitator bear a constant proportional relation such that an increase in the positive gas pressure developed in the lungs is accompanied with a corresponding decrease in the negative gas pressure developed in the lungs.

An object of the present invention is to provide a resuscitator control including means for independently varying the rates of forced inhalation and exhalation.

Another object of this invention is to provide a resuscitator control including means for independently regulating the maximum and minimum gas pressures developed within the resuscitator.

Still another object is to provide a vacuum accumulating means for a resuscitator for creating rapid patient exhalation.

A further object of this invention is to provide a resuscitator control having a dual aspirator assembly wherein one aspirator is employed to dilute or modify the breathing gas supplied to the patient and the other aspirator is employed to evacuate the patients lungs, and wherein novel means are employed to regulate the operation of the dual aspirators.

Still a further, object of this invention is to provide a resuscitator control including counterbalancing means for neutralizing the effects of gravity on the pressure sensing elements of the resuscitator.

Other objects and advantages reside in the construction of parts, the combination thereof, the mode of operation, and the method of manufacture, as will become more apparent from the following description.

In the drawings,

Figure 1 is a perspective view with portions broken away of the preferred embodiment of this invention,

Figure 2 is a sectional view taken substantially along the line 2-2 of Figure l,

Figure 3 is a sectional view taken substantially along the line 3--3 .of Figure ,2,

Patented Mar. 29, 1960 shown in section of a throttle valve of the present inven- Y tion, Figure 10 is a sectional view similar tothat fof Figure 2, but showing the shuttle valve in its reverse position, and

Figure 11 is a sectional view taken along line 11-11 of Figure l.

Referring to the drawings in detail, a housing for the resuscitator control assembly is indicated generally by the reference numeral 10. AV gas inlet port 12 projects from the housing 10 and, when the control assembly is in operation, gas under pressure'from a suitable source is introduced inthe inlet 12. An outlet port 14 projects from the opposite side of the housing 10 and, when the control assembly is in operation, the outlet 14 may be connected to a suitable hoseV for conveying the gaszto a face mask or the like for inhalation bya patient.

The housing 10 comprises four separable parts, a main body portion 16 housing a twin aspirator assembly, a portion 18 supporting the pressure control elements, a portion 20 confining a gas receiving chamber 22, and a cover 2 4. The housing parts 16, 18, 20 and 24 may be secured together in any suitable manner.

The main body portion 16 of the housing lll' is bored adjacent Vthe gas inlet 12 to provide thereina cylindrical cavity 26. The ends of the cavity 26 are closed by threaded screw elements 28, each provided with a resilient bumper 30. Fitted within the cavity 26 is a cylindrical spool valve 32 provided with three annular recesses or grooves 34, 36, and 38, as shown in detail in Figure 7. A boring 40 extends diametrically across the center of the spool valve, the boringl40 opening into the annular groove 36. The spool valve 32 is also provided with an axial boring 42 intersecting the boring 40. As will be described in .detail subsequently, the spool valve 32 is adapted to be actuated reciprocally within theV cavity 26 by the incoming gas, the spool valve shuttling between extreme axial positions within the cavity 26.

The cylindrical cavity 26 communicates with a conduit plate 44 through a plurality of ports 46a, 46b, 46c, 46d and 46e such as shown in Figure l. The conduit plate 44 is secured to the top surface 48 of the main body portion 16 of the housing 10 by suitable screws 50. A suitable gasket, not shown, maybe inserted between the conduit plate 44 and the' surface 48 to insure a gas tight seal therebetween. As shown in detail in Figure 5, the conduit plate 44 is provided with five grooves 52, 54, 56, 58, and 60. Five ports'46a, 46b, 46c, 46d, and 46e, shown in Figure l, extend through the main body portion 16 between the conduit plate 44 and the cylindrical cavity 26, there being one such port aligned with each groove of the conduit plate 44 such that each groove of the conduit plate 44 communicates with the cylindrical cavity 26 through a separate port. The several ports 46 communicate with various portions of the cavity 26 as will be described hereinafter.

When the spool valve 32 is in the extreme axial position shown in Figure 2, thegroove 52"of'the conduit plate 44 communicates through the port 46a with the annular groove 34 of4 the spool valve, thev groove 54 of Y the conduit plate communicates through the port 46b with the annular groove 36, the port 46c communicating with the groove 56 of the conduit plate 44 is sealed from Vt he.cavity,26 by a solidportion 62-of the spool valve 32, the groove 58 of v the-conduitplate 44 communi- Cates-through the p ort 46d with the annular groove 38 of the spool valve, and the port 46e communicating with the groove 6,0 of the conduit plate V44 is sealed from the cavity 26 by the Solid end portion 64 of the spool-valve 32.

When the spool valve 32 is in Atheopposite extreme position, the port 46a and `groove 5,2 VIVaresealed from the cavity 26 by the solid end portion v6.6 of the spool valve; the port 46b and groove 54 are sealed Yfrom the cavity 26 by a solid p ortion 68 ,of the` spool valve; lthe groove-,456 comunicates through 4the sport 46c with ,the annular groove 36; and the grooves 58 and 60 communicate .through the .ports Y46d and L46e, respectively, both with the-.annular groove Y38 of thespool ,valve :32.

Since the gas inlet 12 opens to the annular groove 36 .of-the spool 4valve 32, it .is .apparent 4from `the foregoing that depending upon the position of the spool valve 32 either the groove 54 or the groove 56 ofthe conduit plate 44 may receive gas from the gas inlet 12.

The grooves of the conduit plate 44 communicate with a second cylindrical cavity 70 parallel and adjacent the cavity 26 through five ports 72a, 72b, 72C, 72d, and 72e, as shown in Figure 1. T he cavity 70 is formed by boring the main body portion 16 adjacent the cavity 26. One end of the cavity 70 is closed by `a threaded screw element 74, the .other Vend being .closed .by a .porous filter or screen 76 secured to the main body 16.

An aspirator cylinder 77,.inc'luding two substantially duplicate aspirators, is fixedly mounted within the cavity 70. The first aspirator including a nozzle 78, a vacuum chamber 80, and an outlet -cone 82 functions as a gas dilution aspirator and the second aspirator including a nozzle 84, a vacuum chamber `86, and an outlet cone 88, the latter opening to the ambient atmosphere through the filter 76, functions as a gas evacuation aspirator.

The groove 52 of the conduit plate 44 communicates with the vacuum chamber 80 of the first aspirator through the port 72a, groove 79 and port 79a; the groove S4 of the conduit plate 44 communicates through the port 72b with the nozzle 78 of the first aspirator through a conduit `90 in the cylinder 77; the groove 56 of the conduit plate 44 communicates through the port 72e with the nozzle 84of the second aspirator through a conduit 92 in thecylinder 77; the groove 58 of the conduit plate 44 communicates through the port 72d with an annular groove 94 in the cylinder 77;'and the groove 60'of the conduit plate-44 communicates through the port 72e, groove 83 and port 83a with the vacuum chamber 86 of the second aspirator. r'lhe conduits 90and 92 in the cylinder 77 include radial portions 91, as shown in Figure 9, in alignment with the ports 72b and 72e, respectively, for communication with the grooves 54 and 56 respectively, of the conduit plate 44.

It is apparent from the foregoing that with the spool valve 32 in the position shown in Figure 2, the gas inlet 12 communicates with the nozzle 78 of the first aspirator. Gas may therefore ow from the inlet 12 through the nozzle 78 Vand into the outlet cone 82 of the first aspirator. The outlet cone communicates through a conduit`9,6 in the main body portion 16 to a chamber 98 in 4the housing portion 20, the chamber 98 communicating .with the gas receiving chamber 22 through a slot 100. As gas ows in this manner from the inlet 12 to the gas receiving chamber 22, a partial vacuum is created in the vacuum chamber 80 of the rst aspirator by virtue of the A.gas jet iiowing from the nozzle 78 into. the. outlet cone 8.2,. vThis partial vacuum is utilized. to draw air into the 4gas streamA by the following arrangement.

`A11 inlet vport 102-extends angularly -into the main body portion 16 so as to communicate with the annular groove 34 of the spool valve 32. Disposed in an elbow 103 of the angularly extending inlet port 102 is a set screw 104 provided with a conical end portion adapted to adjustably open and close the inlet port 102 whereby the flow of air therein may be regulated. The air inlet port 102 is covered with a `suitable screen or filter 106 secured to the main body portion 16. With the spool valve 32 in the position shown in Figure 2, air is drawn into the inlet port 102 around the annular groove 34 of the spool valve, up port 46a through the groove 52 of the conduitplate 44, down port 72a to groove 79 and through port 79a to the vacuum chamber 80 of the first aspirator.

Although in the present description the inlet port 102 is utilized to dilute the gas stream with air, it is obvious that a second gas or a medicament may also be mixed with the ugas Ventering theinlet .12. by this means.

When the spool valve .32 is .shuttled to the extreme axial position as shown 4in Figure 10, the gas from the gas inlet is directed to the groove 56 of the conduit plate 44 and from there to the nozzle 84 of the second aspirator. The gas then passes through the nozzle and out the outlet cone 88 of the second aspirator to the ambient atmosphere. A partial vacuum is thereby created in the vacuum chamber 86 of the second aspirator. As described hereinbefore, the spool valve 32 is now located such that the vacuum chamber 86 of the second aspirator communicates through groove 33 to groove 6i) in the conduit plate 44, and then to the annular groove 38 of the spool valve 32. Concurrently, the annular groove 33 of the spool valve 32 communicates with the annular groove 94 in the cylinder 77 through the groove 5S in the conduit plate 44. The annular groove 94 communicates with the chamber 93-in the housing portion 20 through a .conduit 108 inthe main body portion 16.

Thus, when the spool valve 32 is positioned to direct gas from the gas inlet 12 to the .second aspirator nozzle 84, the vacuum chamber 86 simultaneously communi- Cates with the chamber 98 so as to `evacuate gas therefrom. As a consequence gas is evacuated from the gas receiving chamber 22.

From the foregoing, it is established that when the spool valve 32 is in the position shown in Figure 2, gas under pressure, diluted as desired with air, or another gas or vapor, is supplied to the gas receiving chamber 22. When the spool valve 32 is shuttled to the position shown in Figure l0, gas is evacuated from the gas receiving chamber 22. A rsingor falling gas pressure may thus be obtained in the gas receiving chamber 22.

It is noted that when the spool valve 32 is in the position shown in Figure Zand therefore the gas pressure in the chamber 22 is rising, the conduit 108 communicates with the annular groove38 of the spool valve 32. However, there is no opening-whereby gas can escape from the annular groove 38 to the atmosphere. Hence, there is no leakage from the chamber 22 through the gas evacuation system. Similarly, when the spool valve 32 is in the position shown in Figure 10, there is falling pressure in the chamber 22, the air inlet port 102 and the groove S2 of the conduit plate 44 are sealed by the end portion 66 of the spool valve 32 so thatY there will be no leakage of air or gas into the gas chamber 22 through the conduit 96. Thus, the rising and falling gas pressures in the chamber 22 may be effectively employed to force inhalation and exhalation, respectively, of a patients lungs connected with the gas receiving chamber 22 through the outlet port 14.

It is desirable in forced resuscitation to control independently the rate at whichA the patients lungs are filled andthe rate at which the patients lungs are emptied. In the present device, this control vis obtained by independently valving the conduits and 92"through which gas is supplied to the first and second aspirator nozzles 78 and 84, respectively. An adjustable valve screw for adjusting the flow of gas to the rst aspirator nozzle 78 is shown in detail in Figure 9. In Figure 9, a portion of the twin aspirator cylinder 77 is shown in section within the main body portion 16 of the housing 10. The conduit 90 within the cylinder 77 which conveys gas to the rst aspirator nozzle 78 is aligned with a port 72a for connection with the conduit plate 44 as described hereinbefore. To regulate the flow of gas in the conduit 90, a threaded passage 112 is provided in the main body portion 16, the passage 112 extending obliquely into the cylinder 77 t0 the junction of the axial and radial portions of the conduit 98. The threaded valve screw 110 provided with a conical end portion is disposed in the passage 112 and may be rotated so as to throttle the conduit 90 `to any desired extent.

A similar passage 114 accommodating a second threaded valve screw is provided for throttling the conduit 92. The passages 112 and 114 open upon the top surface 48 of the main body portion 16, as clearly shown in Figure l.

ln the foregoing, means whereby one gas inlet is utilized to provide both a rising gas pressure and a falling gas pressure in the resuscitator housing and means for independently'varying the rate of rise and fall of the gas pressure have been described. In the following, means for controlling the upper and lower limits of the gas pressure, and means for automatically cycling the gas pressure in the gas receiving chamber 22 are described.

Enclosing one end of the gas receiving chamber 22 is a resilient flexible diaphragm 120 which may be a plastic or an elastomer or the like. The circular diaphragm 120 is seated upon an annular wall portion 122 of the housing portion 20 and is retained at its periphery by a Wall portion 124 of the main body portion 16. The wall portion 124 is provided with an aperture 126 having a diameter slightly less than that of the diaphragm. The diaphragm 120 provides, in effect, a gasket sealing the gas receiving chamber 22.

The diaphragm 12) is provided with an annular arched portion 128 enabling the central portion of the diaphragm to flex or displace axially without stretching of the material of the diaphragm. The central portion of thediaphragm 120 is re-enforced with metallic discs 130 and 132, there being one disc on either side of the diaphragm. Openings are provided in the center of the discs anddiaphragm for receiving a shaft or rod 134 secured to the diaphragm assembly by washers 136. The washers 136 also draw the discs 130 and 132 into contact with the diaphragm 120. v

In response to rising and falling gas pressures in the chamber 22, the diaphragm 120 is displaced axially away from or into the chamber 22 causing the rod 134 to reciprocate along its axis. The reciprocating action of the rod 134 is utilized to actuate the pressure control apparatus assembled in this housing portion 18.

The housing portion 18 comprises a base portion 138, a piston valve housing 148, a cylindrical portion 142 housing a spring biasing assembly, and an arm 144 providing journals for supporting the shaft 134 and another parallel shaft 146, The shaft 146 terminates Vin a cylindrical piston valve 148 journalled in a cylindrical cavity 150 in the valve housing 140 (see Figure l1). The shaft 146 is thus mounted for reciprocal movement in the housingk portion 18.

A rocking arm 152 is pivotally mounted upon the base portion 138 of the housing portion 18, the rocking arm 152 pivoting about a xed pivot 154 supported by a block 156 xedly mounted upon the base portion 138. A'pin 158 secured to the shaft 134 engages a slot 160 in the rocking arm 152 such that as the shaft 1.34 is reciprocated by the diaphragm 120, the rocking arm 152 is caused to pivot. One end 162 of the rocking arm 152 is yieldingly secured to the shaft 146 by a pair of conical springs 164 retained to the shaft 146 by washers 166. Thus, as the shaft 134 reciprocates the shaft 146 is also constrained to reciprocate by the action of the rocking arm 152 and the As shown in Figure 1l, theend 168 of the rocking arm 152 oppositev the end 162 is provided with a ball bearing 170 projecting through an opening 172 between aligned substantially cylindrical portions 174 and 176 of the cylindrical portion 142 of the housing portion 18. Hollow cups 178 and 178 are slidably mounted in the cylinders 174- and 176 respectively, and bear against the ball bearing 170. The cups are seated against an inwardly directed flange portion 179 which serves to locate a neutral position for the rocking arm 152.

Within the cylinders 174 and 176 are threaded, tubular inserts, 180 and 180', respectively, provided with opposing axial slots 182 and 182', respectively. Each insert 180 and 180 is further provided with an annular inwardly directed ange portion 184 and 184', respectively, at one end thereof adapted to retain thumb screws 186 and 186 respectively, journalled for rotationl therein. The threaded shafts 188 and 188 of the thumb screws engage Wingnuts 190 and 198 respectively, provided with wings 192 and 192', respectively, riding in the slots 182 and 182 respectively, of the tubular inserts. By this arrangement, the thumb screws 186 and 186 may be rotated to drive the wing-nuts 190 and 190', respectively, axially in the tubular inserts 180 and 180', respectively. Each wingnut 190 and 190 engages a spring compressed between the y'wing-nut and the corresponding hollow cups 178 and 178 whereby a yielding force is exerted upon the ball bearing 170. Y

The hollow cups 178 and 178' being biased oppositely 'oy the springs urge the rocking arm 152 tothe neutral position. The spring Within the cylinder 174 is designated by the reference numeral 194 Vand the spring within the cylinder 176 is designated by the reference numeral 196. Although not essential, it is preferable that the springs 194 and 196 are equal in unstressed length and in force constant and have a low rate to prevent any appreciable increase in the load as the spring isl compressed.

Clearly, as shown in Figure 3, the arrangement of parts is such that in the neutral position the rocking ann 152 is parallel to the diaphragm 120. An axial displacement of the diaphragm away from the chamber 22 is opposed by the spring 194. lAn axial displacement of the diaphragm 120 into the chamber 22 is opposed by the spring 196. By adjusting the compression of the springs 1941.and 196 with the thumb screws 186 and 186 respectively, the biasing of the diaphragm 128 in either direction may be adjusted. .Suitable indicia, not shown, may be placed on the housing 10 adjacent the thumb screws 186 and 186 for indicating the amount of bias or predetermined load to be placed upon the diaphragm 120. i

The axial motion of the diaphragm 120 is employed to actuate the spool fvalve 32 through the` reciprocating motion of the piston valve 148 in its housing 146. As shown in Figure l1 a pair of spaced conduits 198 and 288 are provided in the housing opening into the cavity therein. The conduits 198 and 260 are so spaced that the piston valve 148 may close selectively one conduit or the other conduit. The conduits 198 and 200 extend upwardly into the main body portion 16 of the housing 10 to the cylindrical cavity 26 therein, the conduit 198 communicating with one end of the cavity 26, the conduit 208 communicating with the other end of the cavity 26, as shown in Figure 2. The conduits 198 and 200 serve to'provide an opening to atmospheric pressure at each end of the cavity 26, there being ports 202 and 204 in the cover 24 of the housing 18 to insure that each side of the piston valve 148 communicates with the ambient atmosphere. Y

If the spool valve 32 is moving downwardly` and approaching the position shown in Figure 2 and the piston valve 148 is located as in Figure l1, that is, closing the conduit 198, there will be a ow of gas from the gas inlet 12, through groove 36, port 40, and through the boring 42 in the shuttle valve 32 and out of the conduit 200 to the ambient atmosphere. When the valve 32 reaches the end of its stroke and assumes the position shown in Figure 2, then the rubber bumper is contacted by the end 66 of the valve 32 and the passage 260 is sealed and bleeding of gas out port 202 is stopped. Simultaneously, the gas pressure in the chamber 22 is rising and the diaphragm is being displaced away from the chamber 22. As a consequence, the piston valve 148 is being displaced so as to open the conduit 198 and close the conduit 2&9. When this happens gas from the inlet 12is permitted to dow to atmosphere through the 'conduit 198. Accordingly, thc pressure in the end of the'cylindrical cavity 26 adjacent the conduit 200 rises Vand that in the opposite end of the cavity 26 vfalls to atmospheric pressure. The high pressure at one end of thc cavity 26 drives the spool valve 32 to the opposite end of the cavity 26, creating as described hereinbefore a condition of falling pressure in the chamber 22. Clearly, when the pressure falls sufficiently below atmospheric pressure to actuate the piston valve 14S in the reverse direction to the initial position of Figure 3, the spool valve 32 will be returned to the initial position shown in Figure 2, initiating a new cycle.

With only the mechanism described in the foregoing, it is possible that the piston valve 148 and spool valve 30 32 can occupy intermediate positions such that the resuscitator control ceases to cycle properly. To insure positive reciprocal action of the spool valve and piston valve, an escapement or lost motion mechanism is provided, whereby the diaphragm 120 must be displaced a finite distance by the gas pressure before the piston valve 148 can be displaced. i

The escapement mechanism includes a ratchet arm 210 provided with a pin 212 journalled loosely in a bracket 214 lixedly attached to the shaft 134. The bracket 214 is provided with apertures 216 for receiving the pin 212, the apertures being large relative tothe pin providing for considerable play of the ratchet arm 21?. rhe ratchet arm 210 is further provided with a slot 21S for engaging an L-shaped pin 229 mounted in a block 222 xedly secured to the housing portion 18 (see Fig. 8).

The play in the apertures 216 and the slot 218 along the axis of the ratchet arm 21B is taken up by a spring 224 mounted under tension between the end 226 of the ratchet arm 219 and a lug 223 integral with the cylinder 176. The opposite Vend of the ratchet arm 21S is provided with a pair of spaced lugs 236 and 231 engaging a cylinder 232 iixedly mounted upon the shaft 146.

The arrangement of parts is such that as the piston valve 148 is in the position shown in Figure 3, the arm 210 is cocked by the spring 224 such that one lug 2.31 the periphery of the cylinder 232 and the other lug 230 engages one end of the cylinder 232 thereby restricting axial movement of the shaft 146 to the left. 50 As the diaphragm is displaced away from the chamba; 22, the rocking arm 152 is pivoted in the con.. clockwise direction as viewed in Figure 3. Sincet z shaft 146 is restrained by the ratchet arm 215;, counterclockwise motion of the rocking arm 152 merely com presses one of the conical springs 164 without producing axial movement of the shaft 146. Simultaneously, rising gas' pressure in the chamber 22, the ratchet ai 21@ is pivoted by the shaft 134 so as to release the cylinder 232. When the cylinder 232 is eventually released, the energy stored in the conical springs 164 on the shaft 146 drives the shaft 146 Vand therefore the piston valve 148 to a new axial position opening the conduit 198 and closing the conduit 200.

At the same timethe ratchet arm 210 is cockedby the spring 224 in the opposite sense to again restrain movement of the shaft 146, the lug 23 engages the right end of cylinder 232 as viewed in Fig. 3 so as to prevent return of the shaft 14610 its initial position. With the ratchet arm cocked'in this manner the pressure in the chamber 22 must fall below atmospheric pressure a nite amount determined by the spring 196 before the piston valve 148 can return to the initial position of Figure 3.

From the foregoing, it is apparent that the resuscitator control can be adjusted so as to vary (l) the rate of gas pressure rise, or rate of patient inhalation, (2) the maximum gas pressure, (3) the rate of pressure drop, or patient exhalation rate, and (4) the minimum gas pressure in the chamber 22 and the patients lungs.

The resuscitator is balanced for gravitational effects upon the pressure regulating mechanism by placing a counterweight 234 on the rocking arm 152 intermediate the ball bearing and the pivot 154. The counterweight is of suicient mass to balance thel weight of the diaphragm 12), the escapcment mechanism, and the piston valve mechanism, about the pivot 154. Thus, regardless of the orientation of the resuscitator housing 10 in a gravitational eld, the gravitational forces acting on the diaphragm are balanced.

The resuscitator control is provided with relief valves communicating with the chamber 22 permitting a patient to override the resuscitator and inhale or exhale voluntarily. A low pressure relief valve 240 is shown in Figure l1, wherein a disc 242 is seated upon a cylindrical flange 244 integral with the hcusing portion 20. The disc 242 is retained against the ange 244 by a spring 246 affixed at one end to disc 242 and at the other end to the apertured ring 24S which is aixed to and engages the external surface of the housing portion 20. Clearly, when the gas pressure in the chamber 22 reaches a sufiiciently low value, the disc 242 will separate from the ange 244 enabling air to enter the chamber 22 from the ambient atmosphere. The incoming air may be filtered by a suitable filter, not shown, mounted in the ring 248.

A high pressure relief valve 250 is shown in Figure ll wherein a disc 252 is seated within a cylindrical flange 254 upon a conical nozzle portion 256 provided internally of the flange 254. The disc 252 is seated against the nozzle portion 256 by a spring 258 mounted under compression between the disc 252 and an apertured ring 260 secured to the external wall of the housing portion 20. When the gas pressure in the chamber 22 obtains a sui'liciently high value, the disc 252 is separated from the nozzle portion 256 enabling gas to escape the chamber 22. rthe relief valves 241i and 2.50 are designed to operate Within the maximum positive and negative lung pressures that the average person may develop.

The removable conduit plate 44 shown in Figure 5 creates the possibility of making several variations in the operation of the resuscitator. For example, by changing theV location of the grooves disposed in thc conduit plate, the resuscitator may be made to continuously supply gas under pressure or to continuously evacuate gas from the chamber 22. Other variations are also possible.

In some circumstances, it is desired to obtain a very sharp drop in pressure in the chamber 22 for exhalation purposes, that is, a gas evacuation rate greater than can be obtained with an ordinary gas operated aspirator. The modification illustrated in Figures 4 and 6 has been designed specifically to obtain rapid exhalation.

In the modification of Figure 4, a spool valve 270 is litted within the cylindrical cavity 26 of the main body portion 16. A diaphragm, escapement mechanism, and piston valve actuate the spool valve 270 in response to pressure changes in the chamber 22 as described hereinbefore.

The spool valve 270 connectsto a twin aspirator cylinder `272 through .a conduit .plate 274, Vas shown in Fig.

9j ure 6, in the manner described hereinbefore in connection with the description of Figures l, 2, 3, 5, l10 and 11. In the present assembly, the twin aspirator cylinder 272 comprises a first aspirator including a nozzle 276, a vacuum chamber 278, and an outlet cone 280, the latter communicating through the conduit 96 as in the preferred embodiment, and a second aspirator including a nozzle 282, a vacuum chamber 284, and an outlet cone 286, the latter emptying to the ambient atmosphere. The conduit plate 274 is provided with ve grooves 288,

290, 292, 294, and 296, as shown in Figure 6. The severalV grooves of the conduit plate communicate through suitable ports 46 and 72 to the spool valve 270 andthe aspirator cylinder 272 in a manner analogous to that described in connection with the preferred embodiment.

When the spool valve 270 isl in the position shown in Figure 4, an annular groove 298 in the spool valve 270 communicates through the groove 288 of the conduit plate 274, 'groove 279 and port 279a with the vacuum chamber 278 of the rst aspirator. An adjustable air inlet port 300 is connected to the annular groove 298 whereby air, or another gas may be introduced into the vacuum chamber 278. An annular groove 302 of the shuttle valve 270, supplied with gas under pressure from the gas inlet 12, communicates through the groove 290 of the conduit plate 274 with the nozzle 276 of the rst aspirator and also through the groove 292 of the conduit plate 274 with the nozzle 282 of the second aspirator. Thus, with the shuttle valve in the position shown in Figure 4, both aspirators are operated.

An annular groove 304 of the spool valve 270 communicates through the groove 294 of the conduit plate 274, groove 283 and port 283:1 of cylinder 272 with the vacuum chamber 284 of the second aspirator. The groove 296 of the conduit plate communicates with an annular groove 306 in the aspirator cylinder 272 and from there through the conduit 108 to the chamber 22. However, with the spool valve 270 in the position of Figure 4, the groove 296 of the conduit plate is closed off by the solid end portion 308 of the spool valve 270.

It is thus apparent that while gas under pressure is supplied to the gas receiving chamber 22 by the .lirst aspirator, gas is simultaneously being evacuated from the annular groove 304 of the spool valve 270, the partial vacuum in the groove 304 being isolated by the position of spool valve 270 from the gas receiving chamber 22.

An accumulator cylinder 310 is connected to the annular groove 304 of the spool valve 270 through a port 312 in the rnain housing portion 16. An adjustable threaded valve screw 314 is provided for regulating the ygas ow in the port 312. With this arrangement, a partial vacuum may be accumulated in the cylinder 310 while simultaneously gas under pressure is supplied to the gas receiving chamber 22.

When the gas pressure in the chamber 22 rises to a sufficient value, the spool valve 270 is actuated to the opposite extreme position in the cavity 26 as described hereinbefore. When this occurs, the grooves 288 and 290 of the conduit plate 274 are blocked off by the vsolid portions 316 and 318, respectively, of the spool valve 270, thus closing off the supply of air and gas to the rst aspirator. The groove 292 of the conduit plate 274 remains in communication with the gas inlet 12 and the groove 294 of the conduit plate remains in communication with the accumulator so that the second aspirator continues to create a partial vacuum. However, now, the groove 296 of the conduit plate which connects tothe gas receiving chamber 22 is also connected with the annular groove 304 of the spool valve '270 and,` as a consequence,.with the accumulator 310. The accumulated partial vacuum is thus connected to -the gas receiving chamber 22 creating an immediate,

V sharp pressure drop in the gas receiving chamber 22. By adjusting the operation of the second aspirator and 10 the volume of the accumulator, the rapidity of gas evacuation `from the chamber 22 may be adjusted to any desired value.

If it should be desired to remove the accumulator from the modification of Figure 4 and to operate the modification exactly as the preferred embodiment, all that is required is to close the port 312 with the valve screw 314 and modify the conduit plate 274 as shown in broken line detail in Figure 6.

By removing the groove 292 of the conduit plate 274 and substituting therefore the oblique groove 320 shown in broken line detail in Figure 6, the second aspirator may be rendered inoperative when the spool valve 270 is in the position shown in Figure 4 and operative when the spool valve 270 is shuttled to the opposite'extreme With such an arrangement, the oblique groove' operating characteristics of the preferred embodiment of Figures 1, 2', and 3, and has, in addition, the partial vacuum accumulator arrangement for extremely rapid exhalation. Y

Although the preferred embodiments of the device have been described, it will be understood that within the purview of this invention various changes may be made in the form, details, proportion and arrangement of parts, the combination thereof and mode of operation, which generally statedqconsrist in a device capable of carrying out the objects set forth, as disclosed and dened in the appended claims.'

What I claim is:

1. A pressure control assembly comprising, in combination: a housing providing a gas receiving chamber; valve means disposed in said housing and being movable between two extreme positions in said housing; means providing a gas inlet to said housing communicating with said valve means; an aspirator assembly carried by said housing including a nozzle portion, a portion providing a vacuum chamber and a portion providing a gas outlet to theambient atmosphere; rst conduit means providing a gas channel from said gas inlet through said valve means to said gas receiving chamber; a second conduit means providing a' gas channel from said gas inlet through said valve means to the nozzle of said aspirator assembly; third conduit means providing a gas channel from the vacuum chamber of Vsaid aspirator assembly through said valve means to said gas receiving chamber; and means responsive to the gas pressure in said gas receiving chamber for automatically operating said valve means between two extreme positions in said housing, said valve means closing the gas channel provided by said first conduit means when in one extreme position and closing the gas channel provided by said third conduit means when in the other extreme position.

2. A pressure control assembly according to claim l including an accumulator chamber for storing a partial vacuum while fluidk tiows into said gas receiving chamber and fourth conduit means providing a gas channel `from said accumulator chamber to the vacuum chamber of said aspirator assembly.

3. A pressure control assembly according to claim 1 including meansfor regulating independently the ow of gas in each of the gas channels provided by said virst and secondY conduit means.

4. A resuscitator control assembly comprising, in corn-y bination: a housing providinga gasrcceiving chamber; a spool valve mounted for reciprocal movement in said housing; atirst and a second gas inlet means in said housing communicating with said spool valve; rst aspira tor means disposed in said housing including a nozzle, aV vacuum chamber, and an outlet communicating Awith said gas receiving chamber, a first conduit means providing a gas channel from said first gas inlet means passing through said spool valve tothe nozzle of said first aspirator means, second conduit means providing a gas channel from said second gas inlet means `passing through said spool valve to the vacuum chamber of said first aspirator means; second aspirator means vdisposed in said housing including a nozzle, a vacuum chamber, .and an outlet communicating with the ambient atmosphere, third conduit means providing a gas channel from said first gas inlet ,means passing through saidspool Avalve to the nozzle of said `second aspirator means, fourth conduit means providing a gas channel from the vacuum chamber of said second aspirator means'through said spool valve to said gas receiving chamber, and means responsive tothe gas pressure insaid gas receiving chamber for actuating said spool valve between two extreme positions so as to selectively open and close the gas channels passing therethrough.

5. A resuscitator control according to claim 4 including an accumulator chamber for storing a partial vacuum while ud fiows into said gas receiving chamber, a fifth conduit means providing a gas channel from said accumulator chamber to the vacuum chamber of said second aspirator means, and wherein said spool valve closes the gas channels provided by said first and second conduit means when in one extreme position and closes the gas channel provided by said fourth conduit means when in the other extreme position.

6. A resuscitator control according to claim 4 wherein the means for actuating said spool valve includes means for supplying gas from said gas inlet to both ends f said spool valve, means providing a gas passage from each end of said spool valve to the ambient atmosphere, there being two of said gas passages, valve means for selectively closing either of said gas passages, pressure sensitive means responsive to the gas pressure in said gas receiving chamber for operating said valve means between two extreme positions, said valve closing one of said gas passages in one of said extreme positions and closing the other of said gas passages in the other of said extreme positions, andrescapement means retaining said valve means in either of the extreme positions thereof when the pressure in said gas receiving chamber is within predetermined limits.

7. A pressure control assembly comprising, in combination: a housing providing a gas receiving chamber; means providing a gas inlet to said housing; a twin aspirator assembly including first and second aspirator means each including a nozzle, a vacuum chamber and an outlet, the outlets of said first and second aspirator means communicating with said gas receiving chamber and the ambient atmosphere, respectively; a conduit plate secured to said housing and provided with a groove-communicating with said twin aspirator assembly; a valve means disposed between said gas inlet and said conduit plate; first conduit means providing a gas channel from said gas inlet through said valve means to the nozzle of said first aspirator means; second conduit means providing a second gas inlet passing through said valve means to the vacuum chamber of said first aspirator means; third conduit means including `the groove of said conduit plate providing a gas channel from said gas inlet through said valve means to the nozzle of said second aspirator means; fourth conduit means providing a gas channel from the vacuum chamber of said second aspirator means through said valve means to said gas receiving chamber;

and means yresponsive to the Igas pressure in `said gas 12 vided by said fourth conduit means when in the other position.

8. A pressure control assembly according to claim 7 wherein the groove in said conduit plate is so oriented that the valve means when in said other position also closes the gas channel provided by said third means.

9. In a resuscitator valve, in combination: a pressure chamber; a tiexible member sealing one end of said chamber; an operating shaft movable with said flexible member; a pivotally mounted rocking lever structurally linterrelated to be pivoted by said operating shaft; and a counterweight on said lever so positioned and arranged and of sufficient mass as to balance the gravitational forces on said flexible member regardless of the orientation of the Vvalve in a gravitational field.

10. A resuscitator control assembly comprising, in combination: a housing providing a gas receiving chamber; means providing a gas inlet to said chamber; means for regulating the gas pressure in said chamber including pressure sensitive means responsive to the gas pressure in said chamber; valve means actuated by the pressure sensitive means for regulating the gas inlet means; and weight means for counterbalancing the gravitational forces exerted on said pressure regulating means.

1l. The resuscitator control assembly according to claim 10 wherein the weight means includes a rocking arm pivotally mounted in said housing; a shaft carried by said pressure sensitive means and provided with means for engaging said rocking arm in spaced relation to the pivotal axis thereof; and a weight supported by said rocking arm, said weight and said shaft engaging said rocking arm on opposite sides of the pivotal axis thereof.

12. A resuscitator control assembly comprising, in combination: a housing providing a gas receiving chamber, means providing a gas inlet to said housing; means including an aspirator assembly communicating with said gas inlet for providing a variable gas pressure in said gas receiving chamber; means including a pressure sensitive diaphragm for controlling said variable pressure means, and weight means for counterbalancing the gravitational forces exerted upon said pressure sensitive diaphragm.

13. A resuscitator control assembly according to claim 12 wherein the weight means includes a rocking arm pivotally mounted in said housing; a shaft carried by said diaphragm and provided with means for engaging said rocking arm in spaced relation to the pivotal axis thereof, and a weight supported by said rocking arm, said weight and said shaft engaging said rocking arm on opposite sides of the pivotal axis thereof.

14. A resuscitator control assembly comprising, in combination: a housing providing a gas receiving chamber, means providing a gas inlet to said housing; means including an aspirator assembly communicating with said gas inlet for providing a variable gas pressure in said gas receiving chamber; and means for controlling the gas pressure in said chamber including a pressure sensitive diaphragm responsive to the gas pressure in said chamber; valve means actuated by said diaphragm for regulating the fiow of gas in said variable chamber pressure providing means; and an escapement mechanism restraining said valve means when the gas pressure in said gas chamber is within predetermined limits, said escapement mechanism including a cylindrical mass carried by said valve means; a ratchet member provided with spaced parallel lugs pivotally secured to said housing in a position substantially normal to the axis of said cylindrical mass, the spacing between said lugs being less than the axial length of said cylindrical mass; means biasing said ratchet member so as to urge the lugs thereof into engagement with the cylindrical mass; Yand means carried by saidpressure sensitive diaphragm pivotally engaging "said ratchet member; the lugs of said ratchet member pivoting'into and out of engagement with said cylindrical mass when actuated by said pressure sensitive diaphragm. l5. A Aresuscitator control assembly comprising, in

combination: a housing providing a gas receiving chamber; means providing a gas inlet to said housing; means including an aspirator assembly communicating with said gas inlet for providing a variable gas pressure in said gas receiving chamber; and means for controlling the gas pressure in said chamber including a iiexible diaphragm communicating with said gas receiving chamber; a rocking arm pivotally mounted in said housing; a first shaft carried by said diaphragm pivotally engaging said rocking arm in ixed relation to the pivotal axis thereof; said rocking arm being thereby pivoted by said diaphragm in response to gas pressure variations in said gas receiving chamber; gas actuated spool valve means for controlling the flow of gas to said variable gas chamber pressure providing means; piston valve means for controlling the actuation of said spool valve; a second shaftyie'ldingly engaging said rocking arm for actuating said piston valve means; spring means biasing said rocking arm to a I'iXed pivotal position; and escapement means restraining said valve means when the exure of said diaphragm is within predetermined limits.

16. The resuscitator control assembly according to claim 15 including weight means supported by said rocking arm, said weight means and said first shaft engaging said rocking arm on opposite sides of the pivotal axis thereof, whereby said weight means counterbalances the gravitational forces exerted upon said diaphragm.

17. The resuscitator according to claim 15 wherein the gas actuated spool valve means includes a tubular f valve mounted for reciprocal movement in said housing;

means for conveying gas from said gas inlet to the core of said spool valve; and vent means connecting each of y the opposite ends of said valve to the ambient atmosphere; said piston valve means being adapted to open and close said vent means so as to alternately connect each end of said valve to the ambient atmosphere to thereby actuate said spool valve when displaced by said diaphragm. i

18. A resuscitator control assembly comprising, in combination: a housing providing a gas receiving chamber; means providing a gas inlet to said chamber; means Vfor regulating the gas pressure in said chamber including a pressure sensitive diaphragm responsive to the gas pressure in said chamberyvalve means actuated by said pressure sensitive means for regulating the gas inlet means and yielding means biasing said diaphragm for regulating the response of said diaphragm to the gas pressure in said chamber, said yielding means including first spring means opposing movement of said diaphragm in response to a positive gas pressure in said chamber, second spring means opposing movement of said diaphragm in response to a negative gas pressure in said chamber, and means for independently adusting the bias applied by each of said rst and second spring means.

References Cited in the le of this patent UNITED STATES PATENTS 

